“Since 2.40 this afternoon the MPS has responded to an incident in the area of Parliament Square and the senior national coordinator has declared this a terrorist incident.

Although we remain open-minded to the motive, a full counter-terrorism investigation is already underway. This is led by the Met counter terrorism command.

At this stage I will confirm what we know has happened but I will not speculate. We received a number of different reports which included a person in the river, a car in collision with pedestrians and a man armed with a knife. Officers were already in that location as part of routine policing but immediately additional officers were sent to the scene and that included firearms officers. We are working closely with the London ambulance service and the London fire brigade.

I’d like to repeat our request for the public to avoid the following areas: Parliament Square, Whitehall, Westminster Bridge, Lambeth Bridge, Victoria Street up to the junction with Broadway, and the Victoria Embankment up to Embankment Tube station. This is to allow emergency service to deal with this ongoing incident. There is an ongoing investigation being led by the counter-terrorism command and we would ask anybody who has images or film of the incident to pass those to the police.

We know there are a number of casualties, including police officers, but at this stage we cannot confirm numbers or the nature of these injuries.

Our response will be ongoing for some time and it is important that we gather all information and evidence. Public safety is our top priority and we are reviewing our policing stance across London and throughout the capital this afternoon.

There will be additional officers on duty and deployed across the capital. I would like to ask the public to remain vigilant and let us know if they see anything suspicious that causes them concern and, if they do, to dial 999 immediately.

The acting commissioner, Craig Mackey, is being treated as a significant witness as he was at the scene when the incident started. Whilst he is not injured, it would be inappropriate for him to be here to talk about this incident at this stage.

Our thoughts and his thoughts are with all those involved and responding to that incident this evening. I would stress that if anyone has information about today’s incident they are urged to call 0800789321 and I want to stress that if the public have any information or see anything suspicious to dial 999 immediately.”